Replied to the LPG 5v issue on your other thread..
Been down this road many times before! Old ECUs sometimes fail in this way. Usually before the system fails to operate completely the 5v line goes wrong, which leads to incorrect readings such as temperatures, pressures and tank levels, all of which barring tank level throwing calibration off.
While you're connected with the laptop things can seem better because the 5v is held correct by the serial connection - Installs effected by the latter symptom can seem OK while setting up with the laptop but as soon as laptop is disconnected calibration goes wrong. If the serial connection can make all the difference, so too can a 7805 wired to the 5v wire at the serial port (or attaching 5v from elsewhere on the vehicle, since many vehicles use 5v sensors).
Gilbert might disagree... He took the 5v advice on LPGforum (working on someone else's car) a while ago and found it didn't work in that case.
I suppose if the 5v falls to miilivolts, could be that the main power feed voltage is pulled down when the system tries to power solenoids / injectors, i.e. solenoid coil or wiring short. Or 5v could be pulled down by failed pressure sensor. The temp and level signals can't really pull the 5v down even if shorted because of the ECU internal resistor on each sensor between the 5v rail (each sensor forms half of a voltage dividing circuit, meter of which is what respective AD converter gets).
The bit of track coming out of the switch seems ominous too.
Simon
You're welcome. I also meant to include... I would never fit 6mm on a P38, even for a mixer system, but wouldn't replace 6mm with 8mm if I was, say, replacing a mixer system with a sequential system on one. I've driven loads of P38s using 6mm with sequential systems and none of had a problem.
Simon
I just noticed this thread...
I generally go with 8mm for just about everything I convert these days, but that's just because I stock loads of 8mm Faro pipe and many various types of Faro fittings for this diameter, including fittings that (for 8mm Faro) emulate 6mm copper pipe ends.
Like Gilbert said, 6mm is considered OK to around 250hp. Very unlikely there'll be problems due to 6mm on a P38, even running a sequential system (instead of a mixer system).
Even on most stuff that needs 8mm pipe, 6mm fittings are usually ok unless you're dealing with something a fair bit over 300bhp. Even on a 310hp vehicle, which might use a reducer with 8mm inlet, it would be unusual to ask a supplier for a tank valve with 8mm outlet. For reasons that I don't fully understand but have a bit of an idea on, flow of liquid LPG through pipes isn't totally related to minimum diameter within that feed, an 8mm pipe with 6mm fittings will flow more than 6mm pipe with 6mm fittings.
Because tank pressure fluctuates with temperature and pressure versus diameter dictates flow capability, if you don't have problems in the depths of winter you're unlikely to have problems all year round. The first point here also explains 'even running a sequential system' - A mixer system supplies gas at near atmospheric pressure while a sequential system might supply gas at 1.5 bar. Tank pressure minus supply pressure is the pressure that pushes gas down the pipe, so it's possible to get away with smaller diameters on mixer systems for any given bhp.
Simon.
Gilbertd wrote:
Lpgc wrote:
Post contains a couple of minor errors, unlike my posts ;-)
What's that then?
Only messing mate ;-)
Gilbertd wrote:
So if the air filter gets a bit clogged, the mixture will be permanently rich (not enough air) so the short term trims will be going constantly negative to reduce the amount of fuel and get the fuel/air ratio correct again. This will cause...
Would be true of a petrol carb, LPG mixer system or AlphaN based fuel system but isn't true where fuel injection system meters air flow and/or manifold pressure..
Piped in series on my own old Chrysler Grand Voyager because it has a matrix in the front and another in the back (matrix's flow in parallel of course)..The reducer is in series with the joint return pipe from both... Thinking was along Gilbert's lines, I didn't want half the flow through the reducer and one quarter flow through each matrix...
There are a lot of iffs and buts regards temp correction. For starters, it seems AEB don't presume gas temp correction works entirely correctly anyway, because otherwise they wouldn't have thought necessary to have compensation for reducer temperature too. AEB default temp compensation figures are a bit exaggerated and reducer temp shouldn't even enter the equation. On some installs (and where it won't effect neatness etc) I try to fit the gas temp sensor in position where it's least likely to pick up heat from the engine (or radiator) or blown cold by external air while driving. On other installs position doesn't make a great deal of difference... most V8 powered stuff gets hot everywhere under the bonnet anyway. The old advice was to fit the temp sensor as close to injectors as possible, thinking was it is at the injectors where the temperature and pressure of gas matters and gas temp could be effected by pipe temps etc between the reducer and injectors ... But I've come to think that in reality when driving gas is shifting so quickly through the pipes it will have little time to be effected much by pipe temperature / At idle gas is shifting slower but still quickly enough for pipe temp not to have much effect on actual gas temp / Though pipe, injectors and temp sensor are more likely to be effected by under bonnet conditions at idle and with slower moving gas the sensor might be effected more by the temperature of whatever it's mounted in than by the gas. One of the iffs and buts concerns compensation particularly at low pulse duration, because unless the ECU firmware correctly accounts for injector latency and temperature related response, no single set of (default) compensation figures will work properly over all possible configurations of pressure, nozzle size and gas injector pulse duration. I.e. you cannot accurately apply Boyle's law without accurately accounting for how injector response is affected by temperature and accurately accounting for injector latency, but almost all firmware seems to get these factors wrong, so temp compensation is best adjusted on individual installs. But again, not much of an issue on a sequential Rover V8 where pulse duration at idle should be higher than it is on most other vehicles and where the petrol system is very forgiving in terms of fuel trims etc - default compensation seems to work fine on them.
Simon
I can see justification for all above points but it's still true that over 90% of P38s and most other LPG converted vehicles have reducer plumbed in parallel without issues.
Both the parallel method and the series method could mean the heater matrix and reducer each only get half the flow - for obvious reason with the parallel method, the series method can mean twice as much restriction in the same pipe so the total flow can only be as much as the part with the most restriction. Series wouldn't be great with a fairly clogged heater matrix, in fact I have seen certain factory converted Vauxhalls fail to run on LPG due to this problem and during summers have re-piped the reducer in parallel to allow running ob LPG until the owner had the matrix problem sorted (even following matrix repair, parallel can be left in place with no ill effect)..
Which method works best (keeps both reducer and matrix hot) will depend on aspects of the vehicle. Some heater circuits will be capable of flowing a large volume but without much of a head of pressure, others will have limited volume but with a high head of pressure while flow is limited. So, with parallel method and only half as much total restriction, some heater circuits will flow twice as much water in total, meaning a no compromise reducer or matrix flow situation. Other vehicles like some Mercs, intentionally restrict water flow under certain conditions such as engine above idle rpm, seemingly so heater water flow is consistent between idle and off idle, and where you can't tap into the un-metered side on such vehicles series is best. In all honesty as long as the reducer is low enough on a P38 it doesn't seem to make any difference.
Wouldn't want to pipe some reducers in series.. some such as old Bigas only have 10mm water pipe connections...
Simon
The next step should probably be check main live feed and switched live voltages at the ECU when the switch fails to light.
Gilbertd wrote:
Maybe you had an iffy connection on the common supply to the petrol injectors? That would explain the LPG system getting offended and the popping and banging when running on petrol. If you had a high resistance in it anywhere, the LPG system would be seeing something less than 12V so wouldn't wake up and the petrol injectors wouldn't be getting a full supply.
I reckon that's a good call.
Off subject slightly but it' remains an unwritten rule of thumb for installers to avoid connecting LPG ECU's switched live or rpm detection wire to the front cylinder of any bank of cylinders. Not relevant to P38's though!
On ECU's such as Stag and maybe including AEB2568 B suffix the switched live simply throws an internal relay, may be solid state in other ECUs. Main power for ECU outputs (injectors and solenoids) always comes through the fused main battery connection, wouldn't want to draw potential peak of maybe 10 additional amps from the petrol injector live as that could cause problems for some vehicles.
Good that the switch stays lit now, if all other wiring was OK but brown rpm wire was broken would expect the switch to light only momentarily when switched live was 12v.
Measuring voltage between chassis and an earth point can give insight into the condition of the ECU, sometimes voltage here increases when the vehicle is running on gas (when it is powering injectors and solenoids), any such voltage can throw off readings such as pressure / temperatures and can lead to more problematic connection with the laptop.
Sometimes the first sign of ECU trouble is difficulty connecting. Connection can mprove more difficult if the laptop is powered from the car (some earth loop type thing going on?). In some cases ECU's only work properly when they are connected to a laptop, dodgy ECU might benefit from the power connection over the serial link. Again, earthing the ECU chassis can help.
Simon
Orangebean wrote:
Simin- can I assume that any solid black cable is (or is meant to be) an earth?
Lpgc wrote:
While you're under the cover, check the earth wire connections in the loom under the cover are all good.
Simon
Yes but watch out for the rpm wire which is brown inside a black sheath.
Looks like you've found the connection problem with the broken red/black in the Molex connector anyway.. Well, former problem with connection before the switch wouldn't even light. The later fitted Supaseal connectors are much better than Molex though you do see the odd bent pin.
Simon
Later on I'll see if I can dig out the pinout info I made myself years ago, I've never seen an official or online pinout for AEB systems though.
Probably no need, as only difference between 2568 systems is switch and on later looms the additional wires that can be connected to the vehicle's OBD port. Without re-reading the thread I seem to remember Gilbert saying Vogel fitted OMVL systems, though it is Tartarini 2568s that I'd expect to be maybe different regards the switch.
While you're under the cover, check the earth wire connections in the loom under the cover are all good. Check the pins on the ECU itself aren't tarnished particularly on main earth and main power feed.
Simon
I edited since you quoted me OB, bit more info.
As Jackk and Ferryman said, also there should be a tie-wrap holding the cover to the loom where the loom first enters, probably need to cut the tie-wrap.
Did you get my bit that implied it may have worked OK before if the chassis was earthed before (but now with ECU not bolted to chassis you lose this other earth point). Chassis shouldn't need to be earthed but I've found on older ECUs earthing the chassis can help. When I see a problem like yours I measure voltage between chassis earth and battery earth, any voltage above say 0.5 when all solenoids and injectors are working may imply a problem (which can cause analogues signals such as pressures and temperatures to be read incorrectly), sometimes just earthing the chassis can help.
Simon
Morat's point was worth mentioning when he did, the programs do only show 3/4cyl options unless talking to an 8/10cyl ECU.
As there's power on the red/white, are battery live and earth good? And if so, are those earth connections underneath the ECU plug cover good and no corrosion on ECU pins? Was the ECU chassis previously earthed / is it now?
I'm sure you'll be right on the error codes... Just that a common definition of P1000 is 'check cycle not complete', a constant code on Jags after engine start until cycle is completed during current run cycle even without the battery having been disconnected, occurs on other vehicles when battery has been disconnected. Some older vehicles lose IACV calibration when battery is off, especially pre2000 Jeeps. Could also see potential for airflow versus throttle angle related codes occurring until IACV calibration is relearned.. But is TPS working properly?
Simon
I've had maybe most versions of AEB software work in 64bit, sometimes works properly, sometimes works with issues as described above, sometimes doesn't work. I wouldn't by default restart my laptop in 32bit to run what might be a problem combination of software and OS but have had to do so on many occasions. The 3/4 cylinder scenario reads like a case of worked with issues.
Won't break anything, will pick a few OBD codes up though! Yes you're looking for 12v on that wire as it enters the LPG ECU. You could run the test in reverse, i.e. temporarily cut the wire and apply 12v to the LPG ECU side of the cut, LPG system should wake up and the switch should light for a short time.
I only ever used piggy back looms on a couple of my conversions, they hardly make for a neat install but that aside, the occasional P38 has one injector wired with opposite polarity to the other injectors... not a problem normally but if you use a piggy back loom this means the LPG ECU breaks the positive connection to the effected injector rather than the negative. None of this is relevant to your problems but where it applies - with an older AEB ECU it can lead to the system switching OK to LPG but preventing you from switching back to petrol again, with a newer AEB ECU (that has it's own OBD) it leads to the LPG ECU seeing the lack of injector pulse as an error but you can get around this by disabling LPG OBD error reporting (which also disables the switch back to petrol response), with an even newer AEB ECU that is truly sequential it leads to the related LPG injector not pulsing even if the Hemi tickbox is ticked.
Simon
Richard might correct me on this but would think a 99 Thor might have a 5-0v sensor? Though OBD sometimes recompiles this to reflect 0-1v, but then on 99 year would expect most OBD2 readers to show 99% slow trims anyway...
Can we confirm this is a Prins sequential system, not just a Prins single point closed loop system....? The latter wasn't a patch on R90 and AEB based single point closed loop systems...
As memory serves (and I've used this disclaimer too often recently!) the most OBD2 compatible Rover V8 equipped vehicles I've seen have been post 2000 Disco's with EGR, these do show trims correctly over OBD2 in the usual +-25% range.
Simon
Hypothetically speaking, or speaking from experience though Marty... I'm not guessing, recent practical experience, and I'm not saying it has to be XP to be right... I wish I had taken some screen shots of the weird behaviour of some software, in some circumstances, in 64bit though. Stuff/apparent settings I've seen must have been dropped under development, never seen in any properly working AEB software. I have touched on this topic on LPG forum before and even argued the toss with Tinleytech about it.
Lighter note - Would have thought AEB software writers would have learned how to spell the word 'High' by now.. In every version of software since I've been installing, which goes back to before the B suffix ECUs came out, have spelled 'Higth' hehe!
Simon
Hehe, that's what I thought you meant (without seeing other thread), but then I thought... no wouldn't make that mistake ;-)
Win7 32 bit is a good bet on newer machines, most drivers are usually available (for the laptop itself) for modern laptops for win7. On this laptop I have Win10 64bit, Win7 32bit and XP 32bit.... Never managed to get drivers for XP but no probs for Win7.
Simon
The B suffix ECUs aren't new enough to show individual injector pulse duration in the diagnostics screen.The point I made earlier on these ECUs reading only front cylinder petrol duration applies (nod to one of Orangebean's points above) and perhaps applies even more so than on even slightly later boards, because it also probably isn't possible to switch individual cylinders back to petrol.
On only reading petrol injection from 2 cylinders, no... Because this isn't in agreement with the above / even on the latest ECUs you can set number of cylinders to whatever you want (will just return an error if it doesn't see all petrol injector pulses in this case, unless you set Hemi mode which should really read 'engine is capable of cylinder deactivation'), and also because you should be able to set number of cylinders to whatever you want without even running the engine / without even connecting any wiring except for providing it with main power.
I reckon the reason you only got option for 3/4 cylinders was due to running in 64 bit Windows... Again as said before, the only AEB software that seems totally happy in 64bit are some of the V6 versions and not all of those, this occurrence is far from the strangest I've seen!
What versions of software connected before?
What's this about plug leads?
Simon